1. Field of Invention
The present invention relates to a method of vacuum packing frozen seafood and more particularly to a method of and apparatus for vacuum packing frozen peeled shrimp, cooked or uncooked, and the like to produce, for example, even microwave cooking, and an apparatus therefor which includes forming means for forming the packet for the seafood with a smaller thickness in its central area in comparison to its peripheral areas, and further to the resulting pack therefrom.
2. Prior Art & General Background
With respect to food technology generally, it is well known to provide vacuum packed food in packets or pouches for defrosting and cooking of the frozen food in boiling water or in a microwave. In such packing, the packed food is contained in a transparent plastic package made of barrier film, i.e. a film which holds a vacuum and does not "breathe," and the food, while still in its package, is cooked or at least defrosted. Classic examples of such food packaging for immediate home use in for example a microwave oven are the food packages provided by Stouffer's.
In the commercial packaging of such food products, the packs are formed on a continuous, mass production basis, in which upper and lower barrier films are provided with the food placed between them on the lower film, and the individual packets evacuated and sealed and separated. Machines which are used for such packing are called "form, fill and seal" machines.
However, in attempting to apply such technology to the packing of for example frozen, peeled shrimp, which is a highly heat sensitive food product, it was found that such technology did not work, and the end food product, when cooked or defrosted in the package, was heated unevenly. In particular, the shrimp located in the center were under cooked or heated, while on the other hand the shrimp at the peripheral edges were over cooked or heated, by the microwave unit. As a result, such technology has not heretofore been available for products such as shrimp.
One of the problems noted by the inventor was that such machines tended to cause the shrimp to be relatively bunched up in the center of the package in the final sealing step.